FWIW
This is something I do on a daily bases.
All work which requires using on a regular bases or on a daily bases when finished at the end of my day I will save all daily work to 2 different usb flash drives takes but a minute or two.
The reason I save to two usb flash drives in case one of the two usb flash drives becomes corrupt I will have the other as a backup.
To prevent possible corruption make certain to unmount / eject the usb flash drive and then wait a minute before removing the usb flash drive as sometimes files may still be being written to the usb flash drive.